Showing 8 results for Baniasadi
Volume 2, Issue 3 (Autumn 2019)
Abstract
One of the miniaturization of heat transfer equipment is enhancing the convective heat transfer coefficient. The main aim of this study is design and producing a kind of nanofluid based on water and ethylene glycol. Graphene was synthesized via electrochemical method and its successful production was confirmed with XRD, FTIR spectrum and, SEM and TEM images. By using different amount of graphene i.e. 0.25, 0.5, 0.75, 1, 1.25, and 1.5%, water/ethylene glycol/graphene nanofluid was produced. Sodium dodecyl sulfate (SDS) was used as surfactant to improve graphene stability in the base fluid. The designed experimental setup was composed of spiral tube with constant wall temperature and equipped with flow meter and pressure and temperature indicators. Nusselt number and pressure drop were measured for pure water and compared with those obtained from theoretical relations and it was found that the setup works properly. Convective heat transfer coefficient, Nusselt number, and heat transfer rate were investigated for water/ethylene glycol (60/40 wt.%) and nanofluid with different amount of graphene using experimental setup. The results showed that by adding 1 wt.% graphene into the based fluid the convective heat transfer coefficient increased about 50% while pressure drop was also increased about 50%. Overall, the findings of this research work support the potential of water/ethylene glycol/graphene nanofluid for using in heating/cooling equipment.
Volume 2, Issue 6 (10-2005)
Abstract
Volume 3, Issue 1 (Spring 98 2019)
Abstract
Research Subject: Removal of industrial wastewater especially from textile and dyeing factories is always important actions to control of pollutions. Using of polymeric adsorbents is an important method for removal of dyes from industrial wastewater. In this research work, designing and fabrication of PVA-based adsorbent with proper potential for removal of green malachite from industrial wastewater has been reported.
Research Approach: For fabrication of adsorbent 4 wt.% PVA was gelled in the present of 10 wt.% glutaraldehyde as cross-linker and punched. The punched hydrogels were porous with freeze drying method. For improving the adsorption ability, graphene and TiO2 were used. The adsorption of green malachite with prepare adsorbent was measured timely to determine the optimum percentage of nanoparticles. In addition, the effect of contact time and the presence of UV on the adsorption of pollution was investigated. Finally, the adsorption isotherms and thermodynamics study were investigated in different time.
Main Results: The results of adsorption of pollution with PVA/graphene adsorbent in different times showed that 0.5 wt.% is the optimum loading of graphene in the PVA matrix. This value was 3 wt.% for TiO2. The adsorption percentage via optimum adsorbent in dark condition showed that one minute after addition of adsorbent the adsorption percent increased to 75% indicating the high capability of the adsorbent in adsorption of tested pollution. The porous structure was confirmed via SEM image. By comparing the correlation coefficient for Langmuir and Freundlich isotherms it was found that Freundlich isotherm has better agreement with the findings of the current study. In other words, adsorption of green malachite with fabricated adsorbent was done multi layered. The thermodynamics studies showed that due to negative value of Gibbs energy the adsorption reaction of green malachite with fabricated absorbent is automatically.
Volume 4, Issue 2 (Summer 2020)
Abstract
Research Subject: One of the important methods in the treatment of skin wounds is the use of wound dressings. Recently, the use of polymer-based wound dressings has become increasingly common. The use of natural polymers is very important in wound dressings. The aim of the present study is to design and manufacture a polyvinyl alcohol/aloe vera wound dressing with the capability of healing skin wounds.
Research Approach: The electrospinning method was applied to prepare the samples. Aloe vera gel was first extracted, purified, and powdered by freeze-drying. In all samples, the amount of polyvinyl alcohol and aloe vera powder was fixed at 8 wt.%. This value was selected empirically based on the quality of the produced fibers. Different samples including different amounts of polyvinyl alcohol and aloe vera were produced and their properties including morphology, tensile strength, swelling, degradability, and antimicrobial properties were investigated.
Main Results: The results showed that the dropless random oriented fibers with uniform diameter were produced. The diameter increased with increasing aloe vera contribution, which was attributed to an increase in viscosity due to the presence of aloe vera. With increasing aloe vera contribution in the samples, tensile strength decreased and the elongation percentage increased. The swelling behavior of the specimens was evaluated by measuring the weight of the specimens in a simulated skin environment and the results showed that the presence of aloe vera increased the hydrophilic properties of the specimens. Antimicrobial activity of the samples against two gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa was investigated using the disk diffusion method and it was found that the presence of Aloe vera in the samples brought antimicrobial activity against Pseudomonas aeruginosa. Finally, the findings of this study confirm the feasibility of using polyvinyl alcohol /aloe vera for the production of the electrospun wound dressing.
Volume 9, Issue 3 (Summer 2021)
Abstract
Aims: Dermatoglyphic is the study of skin patterns on hands and feet. It has been shown in some studies that specific finger patterns could be a risk factor for breast cancer. Thus, this study aims to evaluate fingerprint patterns and other easy-to-obtain features in the risk of breast cancer.
Instrument & Methods: This descriptive study was conducted in 2020. A dataset containing 462 records included female patients in Imam Khomeini Hospital Complex, Tehran, Iran. The factors' weight was determined by the Information Gain index. Predictive models were built once without fingerprint features and once with fingerprint features using Naïve Bayes, Decision Tree, Random Forest, Support Vector Machine, and Deep Learning classifiers. RapidMiner 9.7.1 Software was used.
Findings: The most important factor determining breast cancer were age, having a child, menopause situation, and menopause age. The best performance was the Random Forest model with accuracy and Area under Curve of a Receiver operating characteristic of 84.43% and 0.923, respectively. The fingerprint patterns feature increased the RF accuracy from 79.44% to 84.43%.
Conclusion: An early breast cancer screening model could be built with the use of data mining methods. The fingerprint patterns could increase the performance of these models. The Random Forest model could be used. The results of such models could be used in designing apps for self-screening breast cancer.
Volume 16, Issue 3 (5-2016)
Abstract
Linear and angular displacement measuring encoders are the most important measuring tools in the industry. Linear encoders are widely used in various positioning applications, such as numerical controlled (NC) machine tools and factory automation, since they are essential for precision positioning systems. In this study, a capacitive-type linear encoder with un-tethered slider is designed. The main components are made of printed circuit films. Hence, the encoder can be set up in thin inter spaces or on curved surfaces. The encoder consists of a long receiver film and a short transmitter film, respectively containing four-phase and two-phase electrodes. The transmitter is used as a slider and the receiver as a stator. In order to designs an unconstrained slider; the encoder employs a unique approach. Electrical power is supplied to the transmitter film by electrostatic induction which removes electric wires from the slider. In this study the encoder was built using a new signal processing circuit and its performance was evaluated. The new signal processing circuit is more compact and facilitates using this encoder for trade purposes. The result of experimental evaluation shows that the encoder has ±20 micrometers error.
Volume 16, Issue 7 (9-2016)
Abstract
Roughness of vanes’ outer surface and that of cooling channels’ inner surface have considerable impact on temperature distribution. Using a rougher surface leads to increased turbulence in near-surface flows and increases the rate of heat transfer. In this study, vane of a C3X turbine cooled via 10 cooling channels was simulated -three-dimensionally- by ANSYS-CFX software based on SST turbulence model, and then the effects of roughness of said surfaces were examined. The results showed that increasing the roughness of the blade’s outer surface, which absorbs the heat of the hot fluid, to values below the threshold of fully rough regime ( Reks < 70 ) makes no significant impact on vane’s surface temperature distribution; but increasing the roughness to values higher than this threshold leads to 8% increase in surface temperature. This indicates that outer surface of the blade should always exhibit a transitionally rough regime. Opposite to the outer surface, increasing the roughness of cooling channels’ inner surface, which transfers the heat to the cooling fluid, found to be the very beneficial, as even a slight increase in the roughness of this surface (within the domain of transitionally rough) decreases the blade’s surface temperature by up to 8%, and improves the hydraulic-thermal performance factor by about 250%.
Volume 25, Issue 2 (2-2023)
Abstract
One way to better appreciate the value of rangelands with the purpose of developing better policies and make sustainable use of these resources is to determine the monetary valuation of the ecosystem services of these rangelands. Thus, the present study aimed to estimate the economic values of provisioning and regulating services of Rig Ishaqabad Rangeland in Kerman Province, Iran. To this end, samples of the soil and vegetation cover of the region were taken. Following conduction of various experiments, the type and texture of the soil and its content of nitrogen, phosphorus, and potassium nutrients, the soil erosion coefficient, and the amount of carbon absorption for each vegetation type were determined. Then, the monetary values of forage production, carbon absorption, oxygen production, soil production, nutrient absorption, and erosion prevention were estimated using the Revealed Preference Approach. According to the findings, in 2019, the total economic value of the rangeland's services was USD 0.54 million; and the values of provisioning and regulating services were USD 260,102.85 and 283,841.77, respectively. In addition, the economic value of vegetation types of Artemisia sieberi-Denderostellera lessertii (Ar si-De Le), Denderostellera lessertii- Peganum harmala (De le-Pe ha), Cousinia congesta (Co co), Calligonum polygonoides- Astragalus sp (Capo- As sp), Artemisia Sieberi-Peganum harmala (Ar si-Pe ha) were USD 115,466.42, 159,045.6, 54,815.14, 85,220.66, and 129,396.78, respectively. Based on the results, the De le-Pe ha vegetation type was of the highest value with a value of 49.07 US dollars per hectare. The calculated monetary values can be a useful tool in determining the long-term rental rate of this rangeland and determine the amount of investment to preserve or restore it.
